JPH0531788A - Manufacture of thin hollow container and device thereof - Google Patents

Abstract

PURPOSE:To make the thin cylindrical part of a container fully thinner even under the condition that the wall thickness of its tubular part is kept to the same thickness as that of the conventional one. CONSTITUTION:After parison 23 is arranged between opened split molds, mold closing is started so as to firstly pinch the parison 23 by closing a pair of upper molds 7a and 7b and a pair of lower molds 8a and 8b. Next, by moving the upper molds 7a and 7b and the lower molds 8a and 8b to the direction parting from each other, the parison 23 is stretched so as to thin the wall thickness of the parison 23. After main body molds 5a and 5b are closed further for mold closing, pressure fluid is introduced in the parison for blow molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a thin-walled hollow container having a thin-walled body portion and a tubular portion integrally formed on at least one end of the thin-walled body portion.

[0002]

2. Description of the Related Art This type of container, when used as a container for storing drug solution or blood in the medical field, does not allow the drug solution or blood to be dispensed when the drug solution or blood contained in the container is dispensed to a patient by spontaneous dropping. It is required to pour out gradually and not to remain in the container. For this reason, it is required that the thickness of the body part be made extremely thin, and that the container itself be naturally deformed due to the outflow of the stored drug solution or blood, and that the container is naturally drip without supplying air. Has been done. Further, the inlet or outlet of this type of container is provided with a tubular portion for connecting to another container, a flexible pipe or the like. This tubular part requires no leakage of chemicals or blood from the connection part, and no invasion of germs from the outside.
It is necessary to increase its rigidity. For this reason, it is desirable that the tubular portion be as thick as possible.

Conventionally, as a method for manufacturing a thin hollow container of this type, Japanese Patent Application Laid-Open No. 60-23922 filed by the applicant of the present invention has been proposed.
There is a method disclosed in No. 2 and described below.

A heated and melted parison is placed between the split molds and then the molds are closed. First, the parison is clamped by a sliding mold projecting inwardly of the split mold to form an upper end tubular portion. And molding the lower end tubular portion and sealing the parison. Then, a pressurized fluid is introduced into the parison to expand the parison, the parison is made thin, and the split mold is closed to mold the body of the thin hollow container.

[0005]

In the above conventional technique, as described above, since the thin-walled body portion is thinned only in the process of inflating the parison, there is a limit to the thinning. To be more specific, if the wall thickness of the tubular portion is increased in order to increase the rigidity of the tubular portion as described above, the wall thickness of the body portion is correspondingly increased. On the contrary, if the thickness of the parison is reduced to reduce the thickness of the body, there is a dilemma that the thickness of the tubular portion is reduced accordingly. For this reason, there has been a problem that it is difficult to reduce the wall thickness to meet the above-mentioned needs.

The present invention has been made in view of the above-mentioned problems of the prior art. Even if the thickness of the tubular portion is the same as that of the conventional example, the thin body portion can be made sufficiently thin. It is an object of the present invention to provide a method for manufacturing a hollow container and an apparatus therefor.

[0007]

In order to achieve the above object, the invention of the method for manufacturing a thin-walled hollow container of the present invention is a thin-walled hollow container having a thin-walled body and a tubular portion integrally at least at one end of the thin-walled body. In the manufacturing method of 1., a set of split molds constituted by a main body mold having a cavity for molding the thin-walled body, and an upper mold and a lower mold having at least one of the cavities for molding the tubular portion. Using
A parison is disposed between the split molds that are opened, and the parison is first sandwiched between the upper mold and the lower mold, and then the upper mold and the lower mold are moved in a direction in which they are separated from each other. Then, the parison is stretched to make it thin, and then the main body mold is closed and the thin body is molded by blow molding.

The thin-walled hollow container manufacturing apparatus used for carrying out the above-mentioned manufacturing method is a thin-walled hollow container manufacturing apparatus having a thin-walled body and a tubular portion integrally at least at one end of the thin-walled body. The upper mold includes a main mold having a cavity for molding a body part, and a pair of split molds composed of an upper mold and a lower mold having a cavity for molding the tubular part on at least one side. The lower mold and the lower mold are linked to the main mold so that when the molds of the pair of split molds are closed, the molds are closed prior to the closing of the main mold and then moved in directions away from each other. It is characterized in that they are connected via.

Further, a cylinder mechanism may be used instead of the link mechanism.

[0010]

[Action] By holding the parison arranged between the pair of molds opened by the mold by the upper mold and the lower mold, and moving the upper mold and the lower mold in the directions in which they are separated from each other, Stretch Paris. As a result, the wall thickness of the part sandwiched between the upper mold and the lower mold of the parison is kept as it is, and the part which becomes the body part of the container is stretched and the wall thickness is reduced. After that, the main mold is closed, and the parison is inflated by blow molding to mold the thin-walled body. As a result, the thickness of the parison of the body is further reduced, and a thin body having a sufficiently thin wall and a tubular portion having sufficient rigidity are formed.

[0011]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a thin plastic container for chemicals manufactured by the method of the present invention (hereinafter, referred to as a plastic container for chemicals).
It is called a "thin hollow container". ) 1 is shown. As shown in FIG. 1, a thin-walled hollow container 1 is formed by connecting a flat-shaped thin-walled body 2 having a very small wall thickness, and shoulders 3a and 3b above and below the thin-walled body 2, respectively. Tubular parts 4a, 4b with thick wall thickness
It consists of As described above, the tubular portions 4a and 4b are required to be as rigid as possible and not deform, and conversely, the thin-walled body portion 2 is required to be low in rigidity and easily deformed. This is for the moment, each tubular part 4
The wall thicknesses of a and 4b are large, and the wall thickness of the thin body portion 2 is that of each tubular portion
It is necessary to make the thickness as thin as possible in comparison with a and 4b.

First, an embodiment of a method of manufacturing the thin hollow container 1 of the present application will be described with reference to FIGS.

FIG. 2 is a plan view of one main body die of the pair of split dies as seen from the surface where the cavity is formed. However, the second fixing member described later is omitted.

One of the main body molds 5a has a cavity 6a for molding the thin-walled body portion 2 including shoulder portions 3a and 3b, and the main body mold 5a has a tubular portion at an upper portion and a lower portion in the drawing, respectively. An upper die 7a and a lower die 8a having cavities 9a and 10a for molding 4a and 4b are provided.

As shown in FIG. 3, in a state where the split mold is opened, the molten parison 23 is extruded from an extrusion head 24 of an extruder (not shown), and the parison 23 is placed between the split molds and then the mold closing is started. First, the pair of upper molds 7a and 7b and the pair of lower molds 8a and 8b are closed to sandwich the parison 23.

Then, the upper molds 7a, 7b and the lower molds 8a, 8b are respectively moved in directions away from each other (vertical direction in the drawing) to stretch the parison 23. As a result, the parison 23 has the upper molds 7a, 7b.
And a portion between the lower molds 8a and 8b, that is,
The portion between the upper tubular portion 4a and the lower tubular portion 4b shown in FIG. 1 is stretched to reduce its wall thickness.

Further, the molds are further closed to separate the upper molds 7a, 7b and the lower molds 8a, 8b into positions where they do not interfere with the pair of main molds 5a, 5b, and
After closing the main body molds 5a and 5b, a pressure fluid is introduced into the parison 23 to inflate it, and the shoulder portion 3
The thin-walled body 2 including a and 3b is blow-molded.

At the time of the blow molding, the parison 23
As described above, since the wall thickness is reduced by being stretched in advance, the wall thickness is further reduced by this blow molding, and the thin-walled body portion 2 having a significantly smaller thickness than the conventional example is formed. can do.

Next, an embodiment of the thin hollow container manufacturing apparatus of the present application will be described with reference to the drawings. Since one set of split molds has the same structure, one split mold will be mainly described below. FIG. 4 is a perspective view showing a part of one of the main molds 5a, one upper mold 7a and one lower mold 8a of the pair of split molds of this embodiment.

One of the main body molds 5a attached to a movable plate of a mold clamping device (not shown) has a projecting portion 15a at its center, and the shoulders 3a, 3b are provided on the front surface of the projecting portion 15a.
Cavity 6a for molding the thin-walled body portion 2 (see FIG. 1) including
Are formed.

Here, the upper molds 7a, 7 of this embodiment are
In order to move b and the lower molds 8a, 8b in a direction of separating from each other after closing the molds of the main molds 5a, 5b when closing the pair of split molds. The link mechanism of will be described.

Plate-shaped first fixing members 11a are fixed to central portions on both side surfaces of the main body mold 5a, and shafts 16a are respectively provided to project from the first fixing members 11a. One end side of the first arm 12a and one end side of the second arm 13a are sequentially rotatably supported by the respective shafts 16a. The other end of each first arm 12a is rotatably attached to a shaft 18a projecting from a support plate 17a fixed to the side surface of an upper mold 7a having a cavity 9a for forming a tubular portion 4a. It is supported. On the other hand, the other end of each second arm 13a is rotatably supported by a shaft 18b protruding from a support plate 17b fixed to the side surface of the lower mold 8a. The second fixing members 14a and 14b are
Two plate bodies 20a and 20b erected vertically (the half of the second fixing members 14a and 14b are cut away in FIG. 4, 20b is omitted) and a plate for fixing the central portion thereof It is formed in an H shape from the body 20c, and is fixed to the base by means (not shown) to form an immovable fixing point.
Pins 21a and 21b are projectingly provided at upper and lower ends of the plate body 20a of the second fixing members 14a and 14b. Each of the first arm 12a and the second arm 13a is formed with a guide hole 19a, 19b extending in the longitudinal direction thereof, and the plate body 20 is provided in each of the guide holes 19a, 19b.
A pair of pins 21a and 21b projectingly provided at both end portions of a are slidably inserted. Although not shown, the other ends of the second fixing members 14a and 14b are formed so as to be able to expand and contract when an unexpected load is applied.

Now, the operation of this embodiment will be described with reference to FIGS. 3, 4 and 5. In the mold open state, the pair of left and right body dies 5a and 5b are separated from each other by the maximum distance, and the pair of pins 21a and 21b projecting from both ends of the plate body 20a respectively guide the first arm 12a. Hole 19a and guide hole 19b of second arm 13a
Has moved relative to the tip part of. Therefore, the upper mold 7a and the lower mold 8a are in a state where they are moved to the portion where the distance between them is the shortest, that is, the position A in FIG.

In the mold open state, the parison 23 is attached to the pair of upper molds 7a and 7b and the pair of lower molds 8a and 8b.
After arranging between them, mold closing is started, and the parison 23 is sandwiched by the pair of upper molds 7a, 7b and the pair of lower molds 8a, 8b to form the upper tubular portion 4a and the lower tubular portion 4b. To do. This makes the Paris 23
Will be sealed.

Then, when the mold closing is further advanced, the pair of pins 21a and 21b at both ends of the plate 20a slide in the guide holes 19a of the first arm 12a and the guide holes 19b of the second arm 13a, respectively. It moves and moves relatively to the first fixing member 11a side. Therefore, both arms 12
a and 13a are expanded around the shaft 16a, and accordingly, the pair of upper molds 7a and 7b and the pair of lower molds 8a and 8b are separated from each other in the vertical direction with the parison 23 held therebetween. , To position B shown in FIG.
This position B is the protruding portion 15 of the pair of main body dies 5a and 5b.
It is located above the upper and lower surfaces of a and 15b in the figure, and does not interfere with the protrusions 15a and 15b of the pair of main body molds 5a and 5b when the molds are subsequently closed. After that, by further proceeding with mold closing, the pair of upper molds 7a, 7b and the pair of lower molds 8a, 8b are respectively protruded from the protrusions 15a, 15 of the pair of main molds 5a, 5b.
The mold is moved to a position where it comes into contact with the upper surface and the lower surface of b shown in the figure, that is, position C in FIG. In this completely closed state, a pressure fluid is introduced into the parison 23 by a supply means (not shown), and blow molding is performed.
The thin hollow container 1 as shown in FIG.

The smooth movement of the pair of upper molds 7a, 7b and the pair of lower molds 8a, 8b described above to the respective positions A, B, C can be made by appropriately setting the guide holes 19a, 19b. It goes without saying that we can achieve it.

Further, the above-mentioned link mechanism is not limited to the one in the above-mentioned embodiment, but it is also possible to adopt, for example, a known Scott Russell mechanism or the like.

Next, another embodiment of the thin hollow container manufacturing apparatus of the present invention will be described with reference to FIG. In this embodiment, instead of the link mechanism, a cylinder mechanism driven by a pressurized fluid is used. Also in this apparatus, since the split molds have the same configuration, one split mold will be mainly described.

The main mold 31a has a protrusion 43 at the center thereof.
a, and the shoulder portion 3a,
A cavity 32a for molding the thin-walled body portion 2 including 3b is formed. Cavity 3 for forming tubular portion 4a
The upper die 33a including 5a is connected to the main die 31a via the rod of the cylinder 37a. The lower mold 34a including the cavity 36a for forming the tubular portion 4b has a groove 40 formed on both side surfaces of the main mold 31a.
It is connected to a rod of a cylinder 39a fixed to a moving base 38a that slides up and down along a. The movable pedestal 38a can be moved up and down by a cylinder 41a fixed to a fixed plate 42a on the side surface of the main mold 31a and its rod. The groove 40a forms a locking portion for retaining in the width direction.

The operation of the above apparatus will be described below.
After placing the parison 23 between the split molds in the state shown in FIG. 6, the mold is closed and the parison 23 is fixed to the pair of upper molds 33a.
And after sandwiching between the pair of lower molds 34a, the cylinder 41a is operated to lower the moving pedestal 38a for fixing the cylinder 39a, thereby separating the space between the upper mold 33a and the lower mold 34a, Thin the parison. At this time, the cylinders 37a, 39a
Is released, and a pair of upper molds 33a and 33b and a pair of lower molds 34a and 34b are released according to the progress of mold closing.
Is moved to the main mold side to complete the mold closing, a driving pin (not shown) is driven into the upper mold cavity, and a pressure fluid is introduced into the parison to perform blow molding, as shown in FIG. The thin hollow container 1 is manufactured.

According to the apparatus shown in this embodiment, since the upper die and the lower die are moved by the cylinder mechanism,
It has the advantages that it is easy to take timing, and even if it is a unified and complicated operation, it can be electrically programmed and is easy to control. Moreover, in this apparatus, since the horizontal position of the upper die is constant, it is possible to effectively use the parison by using the parison cutter.

[0033]

Since the present invention is configured as described above, it has the following effects.

Even if the wall thickness of the tubular portion has a high rigidity as in the conventional example, it is possible to manufacture a thin hollow container in which the wall thickness of the thin-walled body portion is sufficiently thin as compared with the conventional example.

[Brief description of drawings]

FIG. 1 is a perspective view of a plastic container for chemical liquid manufactured by the method of the present invention.

FIG. 2 is a plan view of one of the split molds of the thin-walled hollow container manufacturing apparatus of the present application, as viewed from the surface in which the cavity is formed.

FIG. 3 is a schematic side view showing one step of the method for manufacturing a thin hollow container of the present application.

FIG. 4 is a perspective view of one split mold of one embodiment of the thin-walled hollow container manufacturing apparatus of the present application.

5 is an explanatory view showing a positional relationship when one of the split molds in the embodiment shown in FIG. 4 is closed.

FIG. 6 is a perspective view of one split mold of another embodiment of the thin hollow container manufacturing apparatus of the present application.

[Explanation of symbols]

1 Plastic Container for Chemical Solution 2 Thin Body 4a, 4b Tubular Parts 5a, 5b, 31a Main Body Molds 6a, 6b, 9a, 10a, 32a, 35a, 36a
Cavity 11a First fixing members 12a, 12b, 13a, 13b Arms 14a, 14b Second fixing members 15a, 15b, 43a Projections 19a, 19b Guide holes 20a, 20c Plates 37a, 39a, 41a Cylinder

Claims (3)

[Claims] 1. A method for manufacturing a thin-walled hollow container having a thin-walled body portion and a tubular portion integrally formed on at least one end of the thin-walled body portion, wherein at least one of a main body mold having a cavity for molding the thin-walled body portion is provided. A pair of split molds including an upper mold and a lower mold having a cavity for molding the tubular portion is used, and a parison is arranged between the split molds that are opened, and the upper mold and the First, the parison is sandwiched by the lower mold, and then the upper mold and the lower mold are moved in directions in which they are separated from each other to stretch and thin the parison, and then the main mold is molded. A method for producing a thin hollow container, characterized in that the thin body is closed and blow molding is performed. 2. A manufacturing apparatus for a thin-walled hollow container having a thin-walled body portion and a tubular portion integrally formed on at least one end of the thin-walled body portion, wherein at least one of a main body mold having a cavity for molding the thin-walled body portion is provided. A pair of split molds including an upper mold and a lower mold having a cavity for molding the tubular portion are provided, and the upper mold and the lower mold are closed by the pair of divided molds. At the time of closing the mold prior to closing the main mold, the thin mold hollow container is connected to the main mold via a link mechanism so that the main mold moves in a direction away from each other. Manufacturing equipment. 3. The apparatus for producing a thin hollow container according to claim 2, wherein a cylinder mechanism is used instead of the link mechanism.